Majorana zero modes in the hybrid semiconductor-superconductornanowire is one of the promising candidates for topologicalquantum computing. Recently, in nanowires with a superconductingisland, the signature of Majoran...Majorana zero modes in the hybrid semiconductor-superconductornanowire is one of the promising candidates for topologicalquantum computing. Recently, in nanowires with a superconductingisland, the signature of Majorana zero modescan be revealed as a subgap state whose energy oscillatesaround zero in magnetic field. This oscillation was interpretedas overlapping Majoranas. However, the oscillation amplitudeeither dies away after an overshoot or decays, sharply oppositeto the theoretically predicted enhanced oscillations for Majoranabound states, as the magnetic field increases. Several theoreticalstudies have tried to address this discrepancy, but arepartially successful. This discrepancy has raised the concernson the conclusive identification of Majorana bound states, andhas even endangered the scheme of Majorana qubits basedon the nanowires.展开更多
Axion-like particles(ALPs)are often defined as relatively light pseudoscalar particles and appear in many extensions of the Standard Model.Taking into account constraints on the free parameters from existing searche...Axion-like particles(ALPs)are often defined as relatively light pseudoscalar particles and appear in many extensions of the Standard Model.Taking into account constraints on the free parameters from existing searches and explaining the g-2 deviation,we consider the contributions of ALPs with mass in the range of 1.5GeV展开更多
Based on the quark model the cross section for the e~+e^-→ Z^0/r~*→Ω_(ccc)^(++)Ω_(ccc)^(--) exclusive process is investigated at the tree level. Compared with the Z^0→Ω^-Ω~+ decay, our result shows...Based on the quark model the cross section for the e~+e^-→ Z^0/r~*→Ω_(ccc)^(++)Ω_(ccc)^(--) exclusive process is investigated at the tree level. Compared with the Z^0→Ω^-Ω~+ decay, our result shows that the Z^0 boson favors decaying into charmed baryon pairs. The results are also compared with the calculation of inclusively charmed baryon production.展开更多
This paper purposes an explanation for the recent evidence for the violation of lepton universality in beauty-quark decays at CERN’s Large Hadron Collider. A beauty meson (B<sup>+</sup>) transforms into a...This paper purposes an explanation for the recent evidence for the violation of lepton universality in beauty-quark decays at CERN’s Large Hadron Collider. A beauty meson (B<sup>+</sup>) transforms into a strange meson (K<sup>+</sup>) with the emission of either electron-positron (e<sup>+</sup>e<sup>-</sup>) or muon-antimuon (<span style="white-space:nowrap;"><em>μ</em></span><sup>+</sup><em>μ</em><sup>-</sup>). The ratio (<em>R</em><sub>K</sub>) of branching fractions for B<sup>+ </sup><span style="white-space:nowrap;">→</span> K<sup>+</sup><em>μ</em><sup>+</sup><em>μ</em><sup>- </sup>and B<sup>+</sup><span style="white-space:nowrap;">→</span> K<sup>+</sup>e<sup>+</sup>e<sup>-</sup> decays is measured to be <em>R</em><sub>K</sub> = 0.846 instead of 1 in the violation of lepton universality in the Standard Model. This paper proposes that the violation is derived from the binary isotope mixture of two beauty-quarks, b<sub>7</sub> (4979 MeV mass) and b<sub>8</sub> (143,258 MeV mass) whose masses are calculated from the periodic table of elementary particles. b<sub>7</sub> is the observable B, while b<sub>8</sub> is the hidden B to preserve the generation number symmetry between the three lepton family generations and the three quark family generations in the Standard Model. The preservation of the generation number symmetry forbids b<sub>8</sub> to decay into K<sup>+</sup><em>μ</em><sup>+</sup><em>μ</em><sup>-</sup>. In the transition state involving the virtual particles (<span style="white-space:nowrap;"><em>γ</em></span>, W± and Z<span style="white-space:nowrap;">°</span>) before the decay, b<sub>7</sub> and b<sub>8</sub> emerge to form the binary isotope mixture from B. The rates of emergence as the rates of diffuse in Graham’s law of diffusion are proportional to inverse square root of mass. The rate ratio between b<sub>8</sub>/b<sub>7</sub> is (4979/143,258)<sup>1/2</sup> = 0.1864. Since b<sub>7</sub> decays into K<sup>+</sup>, e<sup>+</sup>e<sup>-</sup>, and <em>μ</em><sup>+</sup><em>μ</em><sup>-</sup>, while b<sub>8</sub> decays into K<sup>+</sup>, e<sup>+</sup>e<sup>-</sup>, and forbidden <em>μ</em><sup>+</sup><em>μ</em><sup>-</sup>, the calculated ratio (RK) of branching fractions for B<sup>+</sup><span style="white-space:nowrap;">→</span> K<sup>+</sup><em>μ</em><sup>+</sup><em>μ</em><sup>-</sup> and B<sup>+</sup><span style="white-space:nowrap;">→</span> K<sup>+</sup>e<sup>+</sup>e<sup>- </sup>is 0.5/(0.1864 × 0.5+ 0.5) = 0.843 in excellent agreement with the observed 0.846. The agreement between the calculated RK and the observed RK confirms the validity of the periodic table of elementary particles which provides the answers for the dominance of matter over antimatter, dark-matter, and the mass hierarchy of elementary particles.展开更多
We investigate the two loop electroweak corrections to B meson rare decays B¯→Xsγand B0s→μ+μ−in the minimal supersymmetry standard model(MSSM)extension with two triplets and one singlet(TNMSSM).The new parti...We investigate the two loop electroweak corrections to B meson rare decays B¯→Xsγand B0s→μ+μ−in the minimal supersymmetry standard model(MSSM)extension with two triplets and one singlet(TNMSSM).The new particle contents and interactions in the TNMSSM can affect the theoretical predictions of the branching ratios Br(B¯→Xsγ)and Br(B0s→μ+μ−),and the corrections from two loop diagrams to the process B¯→Xsγcan reach around 4%.Considering the latest experimental measurements,the numerical results of Br(B¯→Xsγ)and Br(B0s→μ+μ−)in the TNMSSM are presented and analyzed.The findings indicate that the results in the TNMSSM can fit the updated experimental data well,and the new parameters Tλ,κ,λ,clearly affect the theoretical predictions of Br(B¯→Xsγ)and Br(B0s→μ+μ−).展开更多
Using the perturbative QCD approach,we studied the effects of the hadronic structure of photons on the pure annihilation rediative decays B→φγ and B_(s)→(ρ^(0),ω)γ.These decays have small branching fractions du...Using the perturbative QCD approach,we studied the effects of the hadronic structure of photons on the pure annihilation rediative decays B→φγ and B_(s)→(ρ^(0),ω)γ.These decays have small branching fractions due to the power suppression by Λ/mB,which makes them very sensitive to next-leading power corrections.The quark components and the related two-particle distribution amplitudes of a final state photon are introduced.The branching fractions can be enhanced remarkably by factorizable and nonfactorizable emission diagrams.The branching fraction of B→φγ increases by approximately 40 times,and those of B_(s)→ρ^(0)γ and B_(s)→ωγ are on the order of O(10-10).We also note that the ratio of branching fractions of B_(s)→ρ^(0)γ and B_(s)→ωγ is very sensitive to the effects of the hadronic structure of photons.All these results can be tested in future.展开更多
Within the standard model,we have investigated rare Z-boson decays into double heavy quarkonia,Z→VV and Z→VP,with V and P denoting vector and pseudo scalar quarkonia,respectively.It is assumed that the leading-order...Within the standard model,we have investigated rare Z-boson decays into double heavy quarkonia,Z→VV and Z→VP,with V and P denoting vector and pseudo scalar quarkonia,respectively.It is assumed that the leading-order QCD diagrams would give the dominant contributions to these processes,and the corresponding branching fractions,for instance,B(Z→J/ΨJ/Ψ),have been estimated to be approximately 10^(-13)in literature.However,these decays could also happen through electromagnetic transitions Z→Vγ^(*)and Z→Pγ^(*),with the virtual photon transforming into V.Interestingly,the smallness of the vector quarkonium mass can give rise to a large factor m_(Z)^(2)/m_(V)^(2)relative to the QCD contributions,which thus counteracts the suppression from the electromagnetic coupling.We systematically include these two types of contributions in our calculation to predict branching fractions for these decays.Particularly,owing to the virtual photon effects,it is found that B(Z→J/ΨJ/Ψ)will be significantly enhanced,up to 10^(-10).展开更多
In this work,we investigate the quasi-two-body decays B_(c)→D^(*)h→Dπhwithh=(K^(0),π^(0),η,η′)using the perturbative QCD(PQCD)approach.The description of final state interactions of the Dπpair is achieved thro...In this work,we investigate the quasi-two-body decays B_(c)→D^(*)h→Dπhwithh=(K^(0),π^(0),η,η′)using the perturbative QCD(PQCD)approach.The description of final state interactions of the Dπpair is achieved through the two-meson distribution amplitudes(DAs),which are normalized to the time-like form factor.The PQCD predictions on the branching ratios of the quasi-two-body decays B_(c)→D^(*)h→Dπh show an obvious hierarchy:Br(B^(+)_(c)→D^(∗+)K^(0)→D^(0)π^(+)K^(0))=(5.22^(+0.86)_(-0.74))×10^(-6),Br(B^(+)_(c)→D^(∗+)π^(0)→D^(0)π^(+)π^(0))=(0.93±0.26)×10^(-7),Br(B^(+)_(c)→D^(∗+)η→D^(0)π^(+)η)=(2.83^(+0.59)_(-0.52))×10^(-8)and Br(B^(+)_(c)→D^(∗+)η′→D^(0)π^(+)η′)=(1.89+0.40-0.36)×10^(-8).From the invariant mass m Dπ-dependence of the decay spectrum for each channel,one can find that the branching fraction is concentrated in a narrow region around the D*pole mass.Thus,one can obtain the branching ratios for the corresponding two-body decays B_(c)→D^(*+)h under the narrow-width approximation.We find that the branching ratios of the decays B_(c)→D^(*+)h are consistent with the previous PQCD calculations within errors.These predictions will be tested in future experiments.展开更多
Within the framework of perturbative QCD factorization,we investigate the nonfactorizable contributions to the factorization-forbidden quasi-two-body decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=π,K...Within the framework of perturbative QCD factorization,we investigate the nonfactorizable contributions to the factorization-forbidden quasi-two-body decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=π,K.We compare our predicted branching ratios for the B_(()(s))→K_(χc0)→Kπ^(+)π-(K^(+)K^(-))decay with available experiment data as well as predictions by other theoretical studies.The branching ratios of these decays are consistent with data and other theoretical predictions.However,in the Cabibbo-suppressed decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=K^(0),π,the values of the branching ratios are of the order of 10^(-7)and 10^(-8).The ratio R_((χ)_(c0))between the decays B^(+)→π^(+)χ_(c0)→π^(+)π^(+)π^(-)and B^(+)→K^(+)χc0→K^(+)π^(+)π^(-)and the distribution of branching ratios for different decay modes in invariant mass are considered in this study.展开更多
We study two-body B(c)→Mc(π,K) and semileptonic Bc→Mcl^-v^-1 decays with Mc=(J/φ,Xc^0),where Xc^0=X^0(3872) is regarded as the tetraquark state ccuu(dd).With the decay constant fxc^0=(234±52) MeV ...We study two-body B(c)→Mc(π,K) and semileptonic Bc→Mcl^-v^-1 decays with Mc=(J/φ,Xc^0),where Xc^0=X^0(3872) is regarded as the tetraquark state ccuu(dd).With the decay constant fxc^0=(234±52) MeV determined from the data,we predict that B(B^-→Xc^0π^-) =(11.5±5.7)×10^-6,B(B^0→Xc^0K^-0)=(2.1±1.0)×10^-4,and B(Bs^0→Xc^0K^0)=(11.4±5.6)×10^-6.With the form factors in QCD models,we calculate that B(Bc^-→Xc^0π^-,Xc^0K^-)=(6.0±2.6)×10^-5 and(4.7±2.0)×10^-6,and B(Bc^-→J/φμ^-vμ^-vμ,Xc^0μ^-v^-μ)=(2.3±0.6)×10^-2 and(1.35±0.18)×10^-3,respectively,and extract the ratio of the fragmentation fractions to be fc/fu=(6.4±1.9)×10^-3.展开更多
In this paper,we calculate the B_(c)→J/ψhelicity form factors(HFFs)up to twist-4 accuracy by using the light-cone sum rules(LCSR)approach.After extrapolating those HFFs to the physically allowable q^(2)region,we inv...In this paper,we calculate the B_(c)→J/ψhelicity form factors(HFFs)up to twist-4 accuracy by using the light-cone sum rules(LCSR)approach.After extrapolating those HFFs to the physically allowable q^(2)region,we investigate the B_(c)^(+)-meson two-body decays and semi-leptonic decays B_(c)^(+)→J/ψ+(P,V,ℓ^(+)ν_(ℓ)),where P/V stand for light pseudoscalar and vector mesons,respectively.The branching fractions can be derived using the CKM matrix element and the B_(c)lifetime from the Particle Data Group,and we obtain B(B^(+)_(c)→J/ψπ^(+))=(0.136+0.002−0.002)%,B(B^(+)_(c)→J/ψK^(+))=(0.010+0.000−0.000)%,B(B^(+)_(c)→J/ψρ+)=(0.768+0.029−0.033)%,B(B^(+)_(c)→J/ψK^(∗+))=(0.043+0.001−0.001)%,B(B^(+)_(c)→J/ψ_(μ)+ν_(μ))=(2.802+0.526−0.675)%and B(B^(+)_(c)→J/ψτ^(+)ν_(τ))=(0.559+0.131−0.170)%.We then obtain R_(π^(+)/μ+ν_(μ))=0.048+0.009−0.012 and R_(K^(+)/π^(+))=0.075+0.005−0.005,which agree with the LHCb measured value within 1σ-error.We also obtain R_(J/ψ)=0.199+0.060−0.077,which like other theoretical predictions,is consistent with the LHCb measured value within 2σ-error.These imply that the HFFs under the LCSR approach are also applicable to the B+c meson two-body decays and semi-leptonic decays B+c→J/ψ+(P,V,ℓ^(+)ν_(ℓ)),and the HFFs obtained using LCSR in a new way implies that there may be new physics in the B_(c)→J/ψℓ^(+)ν_(ℓ)semi-leptonic decays.展开更多
The world's largest sample of J/ψ events, 1.31 billion events accumulated at the BESIII detector, provides a unique opportunity to investigate η and η physics via two-body J/ψ radiative or hadronic decays. For ma...The world's largest sample of J/ψ events, 1.31 billion events accumulated at the BESIII detector, provides a unique opportunity to investigate η and η physics via two-body J/ψ radiative or hadronic decays. For many η decay channels the low background data samples are up to three orders of magnitude larger than collected in any previous experiment. Here we review the most significant results on η and η obtained at BESIII so far. The analyses range from detailed studies of common decay dynamics, observations of new radiative and Dalitz decays, and searches for rare/forbidden decays with sensitivity up to B~10-5. Finally, prospects of forthcoming runs at the J/ψ peak forη and η physics are discussed.展开更多
The strong decays of the N*(1535) resonance are investigated in an extended chiral quark model by including the low-lying qqqqq components in addition to the qqq component.The results show that these five-quark compon...The strong decays of the N*(1535) resonance are investigated in an extended chiral quark model by including the low-lying qqqqq components in addition to the qqq component.The results show that these five-quark components in N*(1535) contribute significantly to the N*(1535)→ Nπ and N*(1535) → Nη decays.The contributions to the Nη decay come from both the lowest energy and the next-to-lowest energy five-quarks components,while the contributions to the Nπ decay come from only the latter one.Taking these contributions into account,the description for the strong decays of N*(1535) is improved,especially for the puzzling large ratio of the decays to Nη and Nπ.展开更多
Study of the rare and forbidden decays of η/η offers a sensitive probe to test fundamental symmetries of quantum chromodynamics and search for new physics beyond the Standard Model. To study the rare decays of η/η...Study of the rare and forbidden decays of η/η offers a sensitive probe to test fundamental symmetries of quantum chromodynamics and search for new physics beyond the Standard Model. To study the rare decays of η/η to π + π - e + e - , π + π - μ + μ - and e + e - μ + μ - at the BES detector, we developed several event generators based on the vector meson dominant model with finite-width corrections and the pseudoscalar mesons mixing theory. The various distributions from event generators are in good agreement with the theoretical predictions, which indicates that the event generators work very well after implemention in the BES Monte Carlo simulation package. In the BES physics analysis, the performance of the event generators will be improved in accordance with the distributions of different variables of η/η from data and the improvement on the theoretical calculations.展开更多
Considering the experimental constraints on the free parameters of the 331 model with a leptonic sector consistent of five triplets, we investigate the lepton flavor violation(LFV) tau decays τ→μM with M = P and V,...Considering the experimental constraints on the free parameters of the 331 model with a leptonic sector consistent of five triplets, we investigate the lepton flavor violation(LFV) tau decays τ→μM with M = P and V,where P and V denote a pseudoscalar meson(π, η or η′) and a vector meson(ρ0, ω or φ), respectively. We find that the contributions of the 331 model to the LFV decays τ→μM mainly come from the new neutral gauge boson Z′. The 331 model considered in this paper can not make the values of the branching ratio Br(τ→μM) approach the corresponding experimental upper limits.展开更多
It was found that the vector meson pair from the pseudoscalar decays can form an entangled state.In this work we give out detailed explanations on the polarization correlation of the two entangled vector mesons.It is ...It was found that the vector meson pair from the pseudoscalar decays can form an entangled state.In this work we give out detailed explanations on the polarization correlation of the two entangled vector mesons.It is demonstrated that an experimental test of the Clauser-Horne inequality can be carried out through measuring the azimuthal distribution of four pseudoscalars in the cascade decay ηc→ VV →(PP)(PP),and the measurement of this process is feasible with the current running experiments in tau-charm factory.Moreover,a brief discussion on the polarization correlation of the two vector mesons from B → VV decays is also presented.展开更多
FCNC processes offer important tools to test the Standard Model(SM)and to search for possible new physics.In this work,we investigate the s→dννrare hyperon decays in SM and beyond.We find that in SM the branching r...FCNC processes offer important tools to test the Standard Model(SM)and to search for possible new physics.In this work,we investigate the s→dννrare hyperon decays in SM and beyond.We find that in SM the branching ratios for these rare hyperon decays range from 10^-14 to 10^-11.When all the errors in the form factors are included,we find that the final branching ratios for most decay modes have an uncertainty of about 5%to 10%.After taking into account the contribution from new physics,the generalized SUSY extension of SM and the minimal 331 model,the decay widths for these channels can be enhanced by a factor of 2~7.展开更多
We study the semileptonic B/Bs→(D^(?),D^(?)s)lνl decays in the framework of the Standard Model(SM),by employing the perturbative QCD(PQCD)factorization formalism combined with the lattice QCD input for the relevant ...We study the semileptonic B/Bs→(D^(?),D^(?)s)lνl decays in the framework of the Standard Model(SM),by employing the perturbative QCD(PQCD)factorization formalism combined with the lattice QCD input for the relevant transition form factors.We calculate the branching ratios B(B(s)→D^(?)(s)lνl)with l=(e,μ,τ),the ratios of the branching fractions R(D^(?))and R(D^(?)s),and the physical observables Pτ(D^(?)(s)),FL(D?(s))and AFB(τ).The“PQCD+Lattice”predictions for B(B→D^(?)lνl)and R(D^(?))agree with the available experimental measurements within errors.For the ratios R(Ds)and R(D^?s),the"PQCD+Lattice"predictions agree with the other predictions.For Pτ(D^?)and FL(D^?),our theoretical predictions agree with the measured values within errors.Our theoretical predictions of the semileptonic B/Bs decays considered could be tested in the near future by the LHCb and Belle II experiments.展开更多
We study the hadronic decays of ∧c^+ to the final states ∑^+η and ∑^+η, using an e^+e^- annihilation data sample of 567 pb^-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII col...We study the hadronic decays of ∧c^+ to the final states ∑^+η and ∑^+η, using an e^+e^- annihilation data sample of 567 pb^-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII collider. We find evidence for the decays ∧^+→∑^+η and ∑^+η' and with statistical significance of and , respectively. Normalizing to the reference decays ∧^+→∑^+π^0 and ∑^+ω, we obtain the ratios of the branching fractions B(∧C^+→∑^+η)/V(∧^→∑^+π^0)and B(∧C^+→∑^+η)/B(∧C^+→∑^+ω)to be and , respectively. The upper limits at the 90% confidence level are set to be B(∧C^→∑^+η)/V(∧^+→∑^+π^0)<0.58 and B(∧C^+→∑^+η)/B(∧C^+→∑^+ω)<1.2. Using BESIII measurements of the branching fractions of the reference decays, we determine B(∧C^+→∑^+η)=(0.41±019±0.05)%(<0.68%) and B(∧C^+→∑^+η)=(1.34+0.53+0.19)%(<1.9%). Here, the first uncertainties are statistical and the second systematic. The obtained branching fraction of ∧C^+→∑^+η is consistent with the previous measurement, and the branching fraction of ∧C^+→∑^+η is measured for the first time.展开更多
The construction of BESⅢ detector has been finished and the data taking is under plan. Some physics topics on charmonium decays at BESIII experiment are discussed in this paper. The measurement of properties of ηc a...The construction of BESⅢ detector has been finished and the data taking is under plan. Some physics topics on charmonium decays at BESIII experiment are discussed in this paper. The measurement of properties of ηc and η′c at BESⅢ is discussed and the expected precision of the measurement is estimated based on BOSS. Also the XcJ decay and the measurement of hyperon decay parameters are mentioned.展开更多
文摘Majorana zero modes in the hybrid semiconductor-superconductornanowire is one of the promising candidates for topologicalquantum computing. Recently, in nanowires with a superconductingisland, the signature of Majorana zero modescan be revealed as a subgap state whose energy oscillatesaround zero in magnetic field. This oscillation was interpretedas overlapping Majoranas. However, the oscillation amplitudeeither dies away after an overshoot or decays, sharply oppositeto the theoretically predicted enhanced oscillations for Majoranabound states, as the magnetic field increases. Several theoreticalstudies have tried to address this discrepancy, but arepartially successful. This discrepancy has raised the concernson the conclusive identification of Majorana bound states, andhas even endangered the scheme of Majorana qubits basedon the nanowires.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11275088 and 11747318
文摘Axion-like particles(ALPs)are often defined as relatively light pseudoscalar particles and appear in many extensions of the Standard Model.Taking into account constraints on the free parameters from existing searches and explaining the g-2 deviation,we consider the contributions of ALPs with mass in the range of 1.5GeV
基金Supported by the National Natural Science Foundation of China under Grant Nos 11645002,11375205 and 11565006
文摘Based on the quark model the cross section for the e~+e^-→ Z^0/r~*→Ω_(ccc)^(++)Ω_(ccc)^(--) exclusive process is investigated at the tree level. Compared with the Z^0→Ω^-Ω~+ decay, our result shows that the Z^0 boson favors decaying into charmed baryon pairs. The results are also compared with the calculation of inclusively charmed baryon production.
文摘This paper purposes an explanation for the recent evidence for the violation of lepton universality in beauty-quark decays at CERN’s Large Hadron Collider. A beauty meson (B<sup>+</sup>) transforms into a strange meson (K<sup>+</sup>) with the emission of either electron-positron (e<sup>+</sup>e<sup>-</sup>) or muon-antimuon (<span style="white-space:nowrap;"><em>μ</em></span><sup>+</sup><em>μ</em><sup>-</sup>). The ratio (<em>R</em><sub>K</sub>) of branching fractions for B<sup>+ </sup><span style="white-space:nowrap;">→</span> K<sup>+</sup><em>μ</em><sup>+</sup><em>μ</em><sup>- </sup>and B<sup>+</sup><span style="white-space:nowrap;">→</span> K<sup>+</sup>e<sup>+</sup>e<sup>-</sup> decays is measured to be <em>R</em><sub>K</sub> = 0.846 instead of 1 in the violation of lepton universality in the Standard Model. This paper proposes that the violation is derived from the binary isotope mixture of two beauty-quarks, b<sub>7</sub> (4979 MeV mass) and b<sub>8</sub> (143,258 MeV mass) whose masses are calculated from the periodic table of elementary particles. b<sub>7</sub> is the observable B, while b<sub>8</sub> is the hidden B to preserve the generation number symmetry between the three lepton family generations and the three quark family generations in the Standard Model. The preservation of the generation number symmetry forbids b<sub>8</sub> to decay into K<sup>+</sup><em>μ</em><sup>+</sup><em>μ</em><sup>-</sup>. In the transition state involving the virtual particles (<span style="white-space:nowrap;"><em>γ</em></span>, W± and Z<span style="white-space:nowrap;">°</span>) before the decay, b<sub>7</sub> and b<sub>8</sub> emerge to form the binary isotope mixture from B. The rates of emergence as the rates of diffuse in Graham’s law of diffusion are proportional to inverse square root of mass. The rate ratio between b<sub>8</sub>/b<sub>7</sub> is (4979/143,258)<sup>1/2</sup> = 0.1864. Since b<sub>7</sub> decays into K<sup>+</sup>, e<sup>+</sup>e<sup>-</sup>, and <em>μ</em><sup>+</sup><em>μ</em><sup>-</sup>, while b<sub>8</sub> decays into K<sup>+</sup>, e<sup>+</sup>e<sup>-</sup>, and forbidden <em>μ</em><sup>+</sup><em>μ</em><sup>-</sup>, the calculated ratio (RK) of branching fractions for B<sup>+</sup><span style="white-space:nowrap;">→</span> K<sup>+</sup><em>μ</em><sup>+</sup><em>μ</em><sup>-</sup> and B<sup>+</sup><span style="white-space:nowrap;">→</span> K<sup>+</sup>e<sup>+</sup>e<sup>- </sup>is 0.5/(0.1864 × 0.5+ 0.5) = 0.843 in excellent agreement with the observed 0.846. The agreement between the calculated RK and the observed RK confirms the validity of the periodic table of elementary particles which provides the answers for the dominance of matter over antimatter, dark-matter, and the mass hierarchy of elementary particles.
基金Supported by the National Natural Science Foundation of China(12075074,12235008,11535002,11705045)the Natural Science Foundation for Distinguished Young Scholars of Hebei Province,China(A2022201017)+1 种基金the Natural Science Foundation of Guangxi Autonomous Region(2022GXNSFDA035068)the Youth Top-NotchTalent Support Programof theHebei Province,China。
文摘We investigate the two loop electroweak corrections to B meson rare decays B¯→Xsγand B0s→μ+μ−in the minimal supersymmetry standard model(MSSM)extension with two triplets and one singlet(TNMSSM).The new particle contents and interactions in the TNMSSM can affect the theoretical predictions of the branching ratios Br(B¯→Xsγ)and Br(B0s→μ+μ−),and the corrections from two loop diagrams to the process B¯→Xsγcan reach around 4%.Considering the latest experimental measurements,the numerical results of Br(B¯→Xsγ)and Br(B0s→μ+μ−)in the TNMSSM are presented and analyzed.The findings indicate that the results in the TNMSSM can fit the updated experimental data well,and the new parameters Tλ,κ,λ,clearly affect the theoretical predictions of Br(B¯→Xsγ)and Br(B0s→μ+μ−).
基金Supported in part by the Open Project of Shaanxi Collaborative Innovation Center of Industrial Auxiliary Chemistry & Technology (XTKF-2020-01)the Nation-al Science Foundation of China (11705159,11975195)+1 种基金the Natural Science Foundation of Shandong province (ZR2019JQ04,ZR2022ZD26,ZR2020MA093)the Project of Shandong Province Higher Educational Science and Technology Program (2019KJJ007)。
文摘Using the perturbative QCD approach,we studied the effects of the hadronic structure of photons on the pure annihilation rediative decays B→φγ and B_(s)→(ρ^(0),ω)γ.These decays have small branching fractions due to the power suppression by Λ/mB,which makes them very sensitive to next-leading power corrections.The quark components and the related two-particle distribution amplitudes of a final state photon are introduced.The branching fractions can be enhanced remarkably by factorizable and nonfactorizable emission diagrams.The branching fraction of B→φγ increases by approximately 40 times,and those of B_(s)→ρ^(0)γ and B_(s)→ωγ are on the order of O(10-10).We also note that the ratio of branching fractions of B_(s)→ρ^(0)γ and B_(s)→ωγ is very sensitive to the effects of the hadronic structure of photons.All these results can be tested in future.
基金Supported in part by the National Natural Science Foundation of China(11575175,12047502)National Research and development Program of China(2020YFA0406400)。
文摘Within the standard model,we have investigated rare Z-boson decays into double heavy quarkonia,Z→VV and Z→VP,with V and P denoting vector and pseudo scalar quarkonia,respectively.It is assumed that the leading-order QCD diagrams would give the dominant contributions to these processes,and the corresponding branching fractions,for instance,B(Z→J/ΨJ/Ψ),have been estimated to be approximately 10^(-13)in literature.However,these decays could also happen through electromagnetic transitions Z→Vγ^(*)and Z→Pγ^(*),with the virtual photon transforming into V.Interestingly,the smallness of the vector quarkonium mass can give rise to a large factor m_(Z)^(2)/m_(V)^(2)relative to the QCD contributions,which thus counteracts the suppression from the electromagnetic coupling.We systematically include these two types of contributions in our calculation to predict branching fractions for these decays.Particularly,owing to the virtual photon effects,it is found that B(Z→J/ΨJ/Ψ)will be significantly enhanced,up to 10^(-10).
基金Supported by the National Natural Science Foundation of China(11347030)the Program of Science and Technology Innovation Talents in Universities of Henan Province,China(14HASTIT037)the Natural Science Foundation of Henan Province,China(232300420116)
文摘In this work,we investigate the quasi-two-body decays B_(c)→D^(*)h→Dπhwithh=(K^(0),π^(0),η,η′)using the perturbative QCD(PQCD)approach.The description of final state interactions of the Dπpair is achieved through the two-meson distribution amplitudes(DAs),which are normalized to the time-like form factor.The PQCD predictions on the branching ratios of the quasi-two-body decays B_(c)→D^(*)h→Dπh show an obvious hierarchy:Br(B^(+)_(c)→D^(∗+)K^(0)→D^(0)π^(+)K^(0))=(5.22^(+0.86)_(-0.74))×10^(-6),Br(B^(+)_(c)→D^(∗+)π^(0)→D^(0)π^(+)π^(0))=(0.93±0.26)×10^(-7),Br(B^(+)_(c)→D^(∗+)η→D^(0)π^(+)η)=(2.83^(+0.59)_(-0.52))×10^(-8)and Br(B^(+)_(c)→D^(∗+)η′→D^(0)π^(+)η′)=(1.89+0.40-0.36)×10^(-8).From the invariant mass m Dπ-dependence of the decay spectrum for each channel,one can find that the branching fraction is concentrated in a narrow region around the D*pole mass.Thus,one can obtain the branching ratios for the corresponding two-body decays B_(c)→D^(*+)h under the narrow-width approximation.We find that the branching ratios of the decays B_(c)→D^(*+)h are consistent with the previous PQCD calculations within errors.These predictions will be tested in future experiments.
基金Supported by the National Natural Science Foundation of China(11235005,11847141,12105112)the Natural Science Foundation of Jiangsu Education Committee(21KJB140027)the Natural Science Foundation of Huaiyin Institute of Technology(21HGZ012)。
文摘Within the framework of perturbative QCD factorization,we investigate the nonfactorizable contributions to the factorization-forbidden quasi-two-body decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=π,K.We compare our predicted branching ratios for the B_(()(s))→K_(χc0)→Kπ^(+)π-(K^(+)K^(-))decay with available experiment data as well as predictions by other theoretical studies.The branching ratios of these decays are consistent with data and other theoretical predictions.However,in the Cabibbo-suppressed decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=K^(0),π,the values of the branching ratios are of the order of 10^(-7)and 10^(-8).The ratio R_((χ)_(c0))between the decays B^(+)→π^(+)χ_(c0)→π^(+)π^(+)π^(-)and B^(+)→K^(+)χc0→K^(+)π^(+)π^(-)and the distribution of branching ratios for different decay modes in invariant mass are considered in this study.
基金Supported in part by National Center for Theoretical Sciences,National Science Council(NSC-101-2112-M-007-006-MY3)MoST(Mo ST-104-2112-M-007-003-MY3)National Science Foundation of China(11675030)
文摘We study two-body B(c)→Mc(π,K) and semileptonic Bc→Mcl^-v^-1 decays with Mc=(J/φ,Xc^0),where Xc^0=X^0(3872) is regarded as the tetraquark state ccuu(dd).With the decay constant fxc^0=(234±52) MeV determined from the data,we predict that B(B^-→Xc^0π^-) =(11.5±5.7)×10^-6,B(B^0→Xc^0K^-0)=(2.1±1.0)×10^-4,and B(Bs^0→Xc^0K^0)=(11.4±5.6)×10^-6.With the form factors in QCD models,we calculate that B(Bc^-→Xc^0π^-,Xc^0K^-)=(6.0±2.6)×10^-5 and(4.7±2.0)×10^-6,and B(Bc^-→J/φμ^-vμ^-vμ,Xc^0μ^-v^-μ)=(2.3±0.6)×10^-2 and(1.35±0.18)×10^-3,respectively,and extract the ratio of the fragmentation fractions to be fc/fu=(6.4±1.9)×10^-3.
基金Supported in part by the National Natural Science Foundation of China(11765007,11625520,11947406,12047564)the Project of Guizhou Provincial Department of Science and Technology(KY[2019]1171)+4 种基金the Project of Guizhou Provincial Department of Education(KY[2021]030)the China Postdoctoral Science Foundation(2019TQ0329,2020M670476)the Chongqing Graduate Research and Innovation Foundation(ydstd1912)the Fundamental Research Funds for the Central Universities(2020CQJQY-Z003)the Project of Guizhou Minzu University(GZMU[2019]YB19)。
文摘In this paper,we calculate the B_(c)→J/ψhelicity form factors(HFFs)up to twist-4 accuracy by using the light-cone sum rules(LCSR)approach.After extrapolating those HFFs to the physically allowable q^(2)region,we investigate the B_(c)^(+)-meson two-body decays and semi-leptonic decays B_(c)^(+)→J/ψ+(P,V,ℓ^(+)ν_(ℓ)),where P/V stand for light pseudoscalar and vector mesons,respectively.The branching fractions can be derived using the CKM matrix element and the B_(c)lifetime from the Particle Data Group,and we obtain B(B^(+)_(c)→J/ψπ^(+))=(0.136+0.002−0.002)%,B(B^(+)_(c)→J/ψK^(+))=(0.010+0.000−0.000)%,B(B^(+)_(c)→J/ψρ+)=(0.768+0.029−0.033)%,B(B^(+)_(c)→J/ψK^(∗+))=(0.043+0.001−0.001)%,B(B^(+)_(c)→J/ψ_(μ)+ν_(μ))=(2.802+0.526−0.675)%and B(B^(+)_(c)→J/ψτ^(+)ν_(τ))=(0.559+0.131−0.170)%.We then obtain R_(π^(+)/μ+ν_(μ))=0.048+0.009−0.012 and R_(K^(+)/π^(+))=0.075+0.005−0.005,which agree with the LHCb measured value within 1σ-error.We also obtain R_(J/ψ)=0.199+0.060−0.077,which like other theoretical predictions,is consistent with the LHCb measured value within 2σ-error.These imply that the HFFs under the LCSR approach are also applicable to the B+c meson two-body decays and semi-leptonic decays B+c→J/ψ+(P,V,ℓ^(+)ν_(ℓ)),and the HFFs obtained using LCSR in a new way implies that there may be new physics in the B_(c)→J/ψℓ^(+)ν_(ℓ)semi-leptonic decays.
基金Supported by National Natural Science Foundation of China(NSFC)(11565006,11675184,11735014)
文摘The world's largest sample of J/ψ events, 1.31 billion events accumulated at the BESIII detector, provides a unique opportunity to investigate η and η physics via two-body J/ψ radiative or hadronic decays. For many η decay channels the low background data samples are up to three orders of magnitude larger than collected in any previous experiment. Here we review the most significant results on η and η obtained at BESIII so far. The analyses range from detailed studies of common decay dynamics, observations of new radiative and Dalitz decays, and searches for rare/forbidden decays with sensitivity up to B~10-5. Finally, prospects of forthcoming runs at the J/ψ peak forη and η physics are discussed.
基金Supported by the National Natural Science Foundation of China (Grant Nos.10875133 and 10821063)the Chinese Academy of Sciences(Grant No.KJCX3-SYW-N2)
文摘The strong decays of the N*(1535) resonance are investigated in an extended chiral quark model by including the low-lying qqqqq components in addition to the qqq component.The results show that these five-quark components in N*(1535) contribute significantly to the N*(1535)→ Nπ and N*(1535) → Nη decays.The contributions to the Nη decay come from both the lowest energy and the next-to-lowest energy five-quarks components,while the contributions to the Nπ decay come from only the latter one.Taking these contributions into account,the description for the strong decays of N*(1535) is improved,especially for the puzzling large ratio of the decays to Nη and Nπ.
基金Supported by National Natural Science Foundation of China (NSFC) (11175189, 11105101, 10979008)100 Talents Program of Chinese Academy of Sciences (CAS) and Fundamental Research Funds for the Central Universities
文摘Study of the rare and forbidden decays of η/η offers a sensitive probe to test fundamental symmetries of quantum chromodynamics and search for new physics beyond the Standard Model. To study the rare decays of η/η to π + π - e + e - , π + π - μ + μ - and e + e - μ + μ - at the BES detector, we developed several event generators based on the vector meson dominant model with finite-width corrections and the pseudoscalar mesons mixing theory. The various distributions from event generators are in good agreement with the theoretical predictions, which indicates that the event generators work very well after implemention in the BES Monte Carlo simulation package. In the BES physics analysis, the performance of the event generators will be improved in accordance with the distributions of different variables of η/η from data and the improvement on the theoretical calculations.
基金Supported by the National Natural Science Foundation of China under Grant No.11275088the Natural Science Foundation of the Liaoning Scientific Committee under Grant No.201102114Foundation of Liaoning Educational Committee under Grant No.LT2011015
文摘Considering the experimental constraints on the free parameters of the 331 model with a leptonic sector consistent of five triplets, we investigate the lepton flavor violation(LFV) tau decays τ→μM with M = P and V,where P and V denote a pseudoscalar meson(π, η or η′) and a vector meson(ρ0, ω or φ), respectively. We find that the contributions of the 331 model to the LFV decays τ→μM mainly come from the new neutral gauge boson Z′. The 331 model considered in this paper can not make the values of the branching ratio Br(τ→μM) approach the corresponding experimental upper limits.
基金supported in part by the National Natural Science Foundation of China (Grant Nos. 10935012, 10928510, 10821063 and 10775179)CAS Key Project on "τ-Charm Physics (Grant No. KJCX2-yw-N29)+1 种基金the Scientific Research Fund of GUCASthe Project of Knowledge Innovation Program (PKIP) of CAS (Grant No. KJCX2.YW.W10)
文摘It was found that the vector meson pair from the pseudoscalar decays can form an entangled state.In this work we give out detailed explanations on the polarization correlation of the two entangled vector mesons.It is demonstrated that an experimental test of the Clauser-Horne inequality can be carried out through measuring the azimuthal distribution of four pseudoscalars in the cascade decay ηc→ VV →(PP)(PP),and the measurement of this process is feasible with the current running experiments in tau-charm factory.Moreover,a brief discussion on the polarization correlation of the two vector mesons from B → VV decays is also presented.
基金Supported in part by National Natural Science Foundation of China(11575110,11735010,11911530088)Natural Science Foundation of Shanghai(15DZ2272100)and Key Laboratory for Particle Physics,Astrophysics and Cosmology,Ministry of Education
文摘FCNC processes offer important tools to test the Standard Model(SM)and to search for possible new physics.In this work,we investigate the s→dννrare hyperon decays in SM and beyond.We find that in SM the branching ratios for these rare hyperon decays range from 10^-14 to 10^-11.When all the errors in the form factors are included,we find that the final branching ratios for most decay modes have an uncertainty of about 5%to 10%.After taking into account the contribution from new physics,the generalized SUSY extension of SM and the minimal 331 model,the decay widths for these channels can be enhanced by a factor of 2~7.
基金Supported by the National Natural Science Foundation of China (11775117,11235005).
文摘We study the semileptonic B/Bs→(D^(?),D^(?)s)lνl decays in the framework of the Standard Model(SM),by employing the perturbative QCD(PQCD)factorization formalism combined with the lattice QCD input for the relevant transition form factors.We calculate the branching ratios B(B(s)→D^(?)(s)lνl)with l=(e,μ,τ),the ratios of the branching fractions R(D^(?))and R(D^(?)s),and the physical observables Pτ(D^(?)(s)),FL(D?(s))and AFB(τ).The“PQCD+Lattice”predictions for B(B→D^(?)lνl)and R(D^(?))agree with the available experimental measurements within errors.For the ratios R(Ds)and R(D^?s),the"PQCD+Lattice"predictions agree with the other predictions.For Pτ(D^?)and FL(D^?),our theoretical predictions agree with the measured values within errors.Our theoretical predictions of the semileptonic B/Bs decays considered could be tested in the near future by the LHCb and Belle II experiments.
基金Supported in part by National Key Basic Research Program of China(2015CB856700)National Natural Science Foundation of China(NSFC)(11235011,11275266,11335008,11425524,11625523,11635010)+16 种基金the Chinese Academy of Sciences(CAS) Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1332201,U1532257,U1532258)CAS(KJCX2-YW-N29,KJCX2-YW-N45,QYZDJ-SSW-SLH003)100 Talents Program of CASNational 1000 Talents Program of ChinaINPAC and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG(Collaborative Research Center CRC 1044,FOR 2359)Istituto Nazionale di Fisica Nucleare,ItalyKoninklijke Nederlandse Akademie van Wetenschappen(KNAW)(530-4CDP03)Ministry of Development of Turkey(DPT2006K-120470)National Science and Technology fundThe Swedish Research CouncilU.S. Department of Energy under(DE-FG02-05ER41374,DE-SC-0010118,DE-SC-0010504,DE-SC-0012069)University of Groningen(RuG)the Helmholtzzentrum fuer Schwerionenforschung GmbH(GSI),DarmstadtWCU Program of National Research Foundation of Korea(R32-2008-000-10155-0)
文摘We study the hadronic decays of ∧c^+ to the final states ∑^+η and ∑^+η, using an e^+e^- annihilation data sample of 567 pb^-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII collider. We find evidence for the decays ∧^+→∑^+η and ∑^+η' and with statistical significance of and , respectively. Normalizing to the reference decays ∧^+→∑^+π^0 and ∑^+ω, we obtain the ratios of the branching fractions B(∧C^+→∑^+η)/V(∧^→∑^+π^0)and B(∧C^+→∑^+η)/B(∧C^+→∑^+ω)to be and , respectively. The upper limits at the 90% confidence level are set to be B(∧C^→∑^+η)/V(∧^+→∑^+π^0)<0.58 and B(∧C^+→∑^+η)/B(∧C^+→∑^+ω)<1.2. Using BESIII measurements of the branching fractions of the reference decays, we determine B(∧C^+→∑^+η)=(0.41±019±0.05)%(<0.68%) and B(∧C^+→∑^+η)=(1.34+0.53+0.19)%(<1.9%). Here, the first uncertainties are statistical and the second systematic. The obtained branching fraction of ∧C^+→∑^+η is consistent with the previous measurement, and the branching fraction of ∧C^+→∑^+η is measured for the first time.
基金National Natural Science Foundation of China(10491303)100 Talents Program of CAS(U-25)
文摘The construction of BESⅢ detector has been finished and the data taking is under plan. Some physics topics on charmonium decays at BESIII experiment are discussed in this paper. The measurement of properties of ηc and η′c at BESⅢ is discussed and the expected precision of the measurement is estimated based on BOSS. Also the XcJ decay and the measurement of hyperon decay parameters are mentioned.